1. Field of the Invention
The present invention relates to methods for rendering materials inflammable, and in particular, to methods for preparing fireproof feathers.
2. Prior Art
Although readily flammable, feathers and wool are used extensively as cushioning material for cushions, pillows, mattresses and the like, as well as for insulating material in jackets, sleeping bags, comforters and the like to retain body heat.
In the case of the wool, several processes have been proposed to impart fire resistant and fireproof properties. Japanese Patent Applications, Nos. 49-30879 and 50-17596 disclose a processes for preparing fireproof wool in which the ionized form of a metal element such as zirconium, titanium or the like is used as a fire-retarding agent. In this process, absorbtion of the metal ions into the wool is accomplished by ionic binding between metal ions and ionized portions of the wool. This process is not applicable to feathers, however, because the metal ions are poorly absorbed by feathers which contain a large proportion of non-polar amino-acids in comparison with wool.
A conventional process for fireproofing feathers exists in which a fire-retarding agent is applied to the surface of the feathers, for example, dimethylphosphonate oligomer. This process has the disadvantage that the fire-retarding agent tends to be washed away in subsequent processing. Additionally, this process tends to adversely affect the softness of the processed feathers.